Users who are affected by the malware should receive an e-mail from android-market-support@google.com by sometime Tuesday night. Those users will also see an update to the Android Market software named "Android Market Security Tool March 2011." This update removes any effects of the exploit. Within 24 hours of applying the update, you should receive a second e-mail.

Google is taking additional, unspecified measures to prevent this sort of thing in the future.